my iPod had 4.5 gigs left...I just connected it to charge, and it synced something from itunes (I havent added anything since the weekend), and suddenly, I have only 3.97 gigs free. How can I delete my iTunes library from the iPod, and resync it? I have it set up as a firewire HD, but the folders are invisible, and I dont want to screw something up, as I know nothing about that. Thanks